The invention relates to a process for the pyrometallurgical production of high-grade copper by smelting and oxidizing a charge of starting material, and subjecting the resultant treated charge to slagging and reducing steps to complete the refining.
Existing copper refining processes of this type, particularly when carried out on a continuous basis, have exhibited several disadvantages. In particular, they have generally been relatively slow and expensive, since it has been found difficult to obtain sufficiently pure copper on an industrial scale without subjecting the charge to multiple or repeated steps (e.g., smelting) during the process. In addition, it has been found that for separation of the impurities which accumulate on the top of the copper bath during the smelting and oxidizing steps, costly metals and chemicals have been required.
Moreover, with such prior techniques it has been possible to obtain high-grade copper only when the starting material has been of relatively high quality, e.g., high-grade copper ore.
An additional factor limiting the efficiency of refining is the fact that, with existing techniques, the relatively high dispersion of the impure oxides collected on the surface of the bath during smelting and oxidation prevents the effective separation, from the bath, of a significant portion of such impurities, whereby the unseparated impurities adhere to the lining of the smelting and oxidizing furnace. Such adhered impurities become reconverted to metal during the reduction step, thereby increasing the impurities content of the refined copper.